Synthesis and structure of a novel three-dimensional metal selenite containing multidirectional intersecting double helical chains: [Fe2(H2O)4(SeO3)2]

A novel three-dimensional metal selenite [Fe₂(H₂O)₄(SeO₃)₂] (1) has been hydrothermally synthesized and characterized by the elemental analyses, IR spectrum, TG analysis and the single crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic system, space group P21/n, with a=6.5283(13) Å, b=8.8754(18) Å, c=7.6798(15) Å, (=98.82(3)β, V=439.71(15) Å3, and Z=2. Compounds 1 exhibits interesting three-dimensional structure constructed from {FeO₆} octahedra and {SeO₃} pyramids linked via the corner- and/or edge-sharing mode. The most interesting structural feature of compound 1 is that the existence of multidirectional intersecting double helical chains in one compound.